Pinch valve

ABSTRACT

An elastomeric sleeve is placed under axial compression in a pinch valve assembly. The axial compression of the sleeve eliminates any crevices with end members that engage opposed end walls of the valve body. Further, axial compression extends cycle life of the valve by maintaining the sleeve in a non-tensile relationship. Mechanical gripping of enlarged flanges defined at opposed ends of the sleeve is also enhanced through axial compression of the sleeve. A positive, visual indication of valve open and closed positions is provided by an indicator stem extending outwardly from an actuator body. In an alternate embodiment, the flanges are reinforced. Additionally, a casing member is interposed between the valve body and sleeve for ease of replacement and maintenance. In still another embodiment, a vent opening in the valve body eliminates pneumatic closure forces on the elastomeric sleeve that can arise when the pinch valve is heated. The vent opening can also be connected to a valve to provide selective venting of the valve body.

This application is a continuation-in-part of Ser. No. 177,971, filedApr. 5, 1988, now U.S. Pat. No. 4,800,920.

BACKGROUND OF THE INVENTION

This invention pertains to the art of fluid flow regulation and moreparticularly to shutoff type flow valves. The invention is particularlyapplicable to a type of valve known as a pinch valve for use in abiotechnological environment. The pinch valve incorporates a flexible,substantially tubular member that is selectively compressed along anexterior portion to close a central flow passage and will be describedwith particular reference thereto. However, it will be appreciated thatthe invention has broader applications and may be advantageouslyemployed in other environments and applications.

Handling of biotechnological components requires an ultra-cleanenvironment and special safeguards to minimize damage to biologicalmaterial such as elongated chains. Specifically, a smooth, reliableshutoff arrangement is required and dependable drainability of the flowline is necessary to prevent entrapment of the biological material. Onlycertain types of materials may be utilized in the valve construction dueto the potential for interaction with the biological material in thefluid.

Typically, pinch valves incorporate a flexible or elastomeric sleevethat is compressed along an exterior portion to selectively open andclose a central fluid passage defined through the sleeve. The life cycleof such a flexible sleeve is dependent on the strength and wearcharacteristics of the elastomeric material. Particularly, closing thevalve places the sleeve under tensile forces which, with repeatedflexing or cycling, tends to become stretched and unusable.

For example, U.S. Pat. No. 3,350,053 to Schmitz, issued Oct. 31, 1967,describes some of the problems inherent with pinch valves utilized inthe industry. One solution proposed in that patent to the repeatedflexing of the elastomeric sleeve is to reduce the diameter to lengthratio of the valve body and sleeve to as low a value as possible. It isbelieved that this ratio reduction provides a compact structure thatlimits the stretching of the resilient material of the sleeve.

Another avenue of attack for increasing the cycle life of the sleeve isto limit forces tending to pull end flanges of the sleeve toward thecenter of the valve. The solution offered by the Schmitz patent to thisproblem is to employ a preselected bulge molded into the sleeve betweenthe end flanges. In this manner, the sleeve is positioned in anunstretched, slack arrangement and a valve actuating member has apredetermined range of movement that takes up the slack molded into thesleeve. Thus, the sleeve experiences reduced, if any, tensile forces asa result of actuator movement to a closed position. Although suitablefor some fluid applications, it is considered desirable to eliminate thebulge molded into the sleeve in other applications because of thepotential entrapment of biological material and variation in the flowpassage configuration that disrupts the pursuit of laminar flowconditions.

Yet another problem associated with remotely operated valves of thistype is the lack of any indication of the valve open and closedpositions. It is critical to readily determine whether or not fluid flowis shut off so that downstream operations for repair, servicing, and thelike may be conducted. Prior pinch valve structures have failed toadequately address this situation.

Still another area of concern is the drainability of the valve that maybe effected through the type of actuation mechanism or repeated flexingof the valve sleeve. Although the elastomeric materials utilized in themakeup of the valve sleeve have resilient properties, continued flexingor cycling results in stretching or permanent deformation of the valvesleeve. If the sleeve is closed through the application of peripheralforces along a bottom portion of the sleeve as is common in prior pinchvalve structures, stretching or deformation may result. This, in turn,inhibits drainability of the valve after the valve has been in use foran extended period of time since fluid upstream of the actuating area ofthe sleeve will not freely drain along the bottom portion.

As indicated above, some pinch valve arrangements utilize end flanges inan effort to grip the valve sleeve in the body. The use of flanges hasmet with substantial commercial success but the sleeve configuration hasprovided some difficulty in maintenance and replacement situations.

The necessity for an ultra-clean environment requires that componentshandling biological materials be frequently and thoroughly cleaned. Forexample, prior valves have been autoclaved, i.e., subject to sterilizingaction using superheated steam under pressure. The entire valve body isheated during the sterilizing process, which heating can have adverseeffects on the operation of the valve.

The subject invention contemplates a new and improved pinch valvearrangement that overcomes all of the above referenced problems andothers and provides as easily assembled, reliable valve structure.

SUMMARY OF THE INVENTION

According to the present invention, there is provided an improved pinchvalve arrangement particularly adapted for biotechnologicalenvironments.

According to a more limited aspect of the invention, the valve includesa rigid body having an opening for receiving a flexible sleeve therein.The flexible sleeve has an unstressed, predetermined axial dimensiongreater than a stressed, second axial dimension. First and second endmembers are received on either end of the body for retaining the sleeveagainst axial movement. The end members place the sleeve undercompression thereby reducing the axial dimension of the sleeve.

According to another aspect of the invention, a casing member is closelyreceived in the valve body and closely receives the flexible sleevetherein to aid in maintenance and replacement of the sleeve.

According to yet another aspect of the invention, the sleeve includesreinforcing rings secured at opposite ends.

According to a further aspect of the invention, means for minimizingtorque transmission to an actuating plunger is provided.

According to a still further aspect of the invention, means for ventingthe valve body may be included.

According to another aspect of the invention, the casing member isconfigured to accommodate lateral expansion of the flexible sleeveduring closure.

According to still another aspect of the invention, the reinforcingrings include plural openings to aid in elastomer flow duringmanufacture of the reinforced sleeve.

A principal advantage of the invention resides in the improved operationof the valve sleeve.

Yet another advantage is found in the ultra-clean valve that resultsfrom this structure.

Still another advantage is realized in the ease of replacing ormaintaining the valve sleeve.

Still other advantages result from selective venting of the valve body.

Still other advantages and benefits of the invention will becomeapparent to those skilled in the art upon a reading and understanding ofthe following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may take physical form in certain parts and arrangementsof parts, preferred embodiments of which will be described in detail inthis specification and illustrated in the accompanying drawings whichform a part hereof, and wherein:

FIG. 1 is a vertical, longitudinal cross-sectional view of a pinch valveconstructed in accordance with the subject invention;

FIG. 2 is a view generally along the lines 2--2 of FIG. 1;

FIG. 3 is a cross-sectional view of the valve sleeve according to thesubject invention;

FIG. 4 is an enlarged, cross-sectional view illustrating the stressedand unstressed states of the elastomeric sleeve and cooperation with thevalve body;

FIG. 5 is a modified arrangement of a fluid operated actuator;

FIG. 6A is a representation of the valve sleeve and actuating member ina valve open position;

FIG. 6B is a representation of the actuating member and sleeve in avalve closed position;

FIG. 7 is a longitudinal cross-sectional view of a modified pinch valvestructure;

FIG. 8 is a longitudinal cross-sectional view of a manually actuatedarrangement of the modified pinch valve structure of FIG. 7;

FIG. 9 is a longitudinal cross-sectional view of another modified pinchvalve structure;

FIG. 10 is an exploded perspective view of a modified casing member;

FIG. 11 is a perspective view of the underside of one of the casingmember components illustrated in FIG. 10;

FIG. 12 is a view of a pinch valve in an open position incorporating themodifed casing member of FIGS. 10 and 11;

FIG. 13 is a view similar to FIG. 12 but illustrating the valve in aclosed position; and,

FIG. 14 is a plan view of a modified reinforcing ring for incorporationinto a pinch valve sleeve.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings wherein the showings are for purposes ofillustrating the preferred embodiments of the invention only and not forpurposes of limiting same, the FIGURES show a pinch valve A having acentral valve body B, a flexible elastomeric sleeve C, actuatingmechanism D, and opposed valve body end members E.

More particularly and with reference to the embodiments of FIGS. 1-6,the valve body is of rigid construction, preferably stainless steel. Afirst axial bore 10 extends through the body for receipt of theelastomeric sleeve. First and second counterbores 12, 14 are disposed atopposite ends of the bore for reasons which will become more apparenthereinbelow. Each counterbore defines a generally radially extendingshoulder 16 with the bore. The shoulders 16 are configured to extendaxially inward as they extend radially outward from the bore to therespective counterbore sidewall.

The sleeve C includes a generally cylindrical central portion 22 havingan outer peripheral dimension closely received in the bore 10. Enlargedradially extending flanges 24, 26 are defined at opposite ends of thesleeve. The flanges increase in axial dimension as they extend radiallyoutward from a central opening 28 of the sleeve. That is, theconfiguration of the flanges approximates the configurations ofcounterbores 12, 14 in which they are respectively received.

The end members E are received on opposite ends of the central valvebody B to matingly engage first and second end walls 34, 36 of the valvebody. Specifically, generally planar walls 38, 40 abuttingly engage theend walls 34, 36, respectively. A first groove 42 is defined in the endwall 34 to receive seal member 44 and, likewise, second groove 46 isdefined in end wall 36 to receive a seal member such as O-ring 48. Theseal members provide a back-up seal arrangement between the centralvalve body and end members as will become more apparent below. Since theend members are of identical construction, description of one end memberwill be equally applicable to the other end member unless notedotherwise.

An enlarged portion 54 of end member E is disposed adjacent the valvebody and includes four generally equally spaced openings 56, 58, 60, 62adapted to receive fastening means such as nut and bolt type fasteners66, 68, 70, 72. The fasteners extend freely through the enlargedportions of the end members and three of them, namely, 66, 68, 70 aredisposed along peripheral portions of the valve body B (FIG. 2). Thefourth fastener 72 extends through a lobe portion 80 of the centralvalve body. The lobe portion includes an axially extending opening 82that is concentric with openings 62 of the end members when the valve isassembled.

As detailed in commonly assigned U.S. Pat. No. 3,954,251 to Callahan,Jr., et al., issued May 4, 1976, this valve body and fastenerarrangement provides a swingout feature of the central valve bodyrelative to the valve body end members by removal of a single fastener.Particularly, removal of fastener 66 permits the valve body to rotatearound fastener 72 in a counterclockwise manner as illustrated by arrowF. This structural arrangement facilitates ease of replacement of theseal members 44, 48 or provides access to the elastomeric sleeve C ifreplacement or maintenance is necessary. Throughout the change-overprocess, the central valve body is held in axial position relative tothe end members such that proper realignment is achieved merely byrotating the central body back into its original position shown in FIG.2. Since details are described in the noted patent and form no part ofthe subject invention, further discussion herein is deemed unnecessary.

The end members also include through passages 84 that define either aninlet or an outlet to the central valve body. Suitable connectionsbetween the through passages and an associated fluid system can be madethrough well known pipe or fluid connection means as conventionally usedin the art. When the valve is assembled, the passages 84 and sleeveopenings 28 define a straight flow-through passage of substantiallyconstant diameter that limits potential shearing of the biologicalmaterial in the fluid and promotes laminar flow.

As illustrated in FIGS. 1 and 2, a bore 86 extends through the centralvalve body and generally perpendicular to bore 10. Counterbore 88extends coaxially from bore 86 defining a radial shoulder 90 therewith.The actuating mechanism D includes a closure member 96 having a reduceddiameter tip 98 dimensioned for close receipt through bore 86. The tip98 preferably has a rounded end for engagement with cylindrical portion22 of the sleeve as will be described in greater detail below. The tipcan have a blade-like configuration as apparent in FIGS. 1 and 2 or acylindrical configuration as illustrated in FIGS. 6A and 6B. Of course,still other tip configurations having a rounded end can be used withoutdeparting from the scope and intent of the subject invention.

A seal member such as O-ring 100 is received in a peripheral groove 102on the closure member to seal between the closure member and counterbore88. According to the preferred embodiment, the closure member cooperateswith a biasing means such as spring 104. The spring has a first or lowerend 106 received in an annular recess 108. The second or upper end 110of the spring is received in an annular groove 120 of closure memberpiston 122. Receipt of opposite ends of the spring in the recess andgroove maintains alignment of the closure member in counterbore 88 andnormally biases the closure member outward to a valve open position. Aseal member such as O-ring 124 is received in a peripheral groove 126 ofthe piston to sealingly engage a second enlarged counterbore 128. Aclosure cap 130 is threadedly received in an upper end of the valve bodyand is sealingly engaged therewith by means of yet another seal membersuch as O-ring 132. Additionally, an inner end of the closure cap has areduced diameter recess 134 that extends outwardly from a stop shoulder136 that limits outward biasing movement of the piston and closuremember. Shoulder 138 defined between counterbores 88, 128 defines a stopsurface that limits inward movement of the piston.

An opening 140 is defined in the recess 134 and receives a stem 142therethrough extending outwardly from an upper face of the piston. Inthe embodiment of FIGS. 1 and 2, the stem is slidably and sealinglyreceived through the opening by means of seal member 144. Thus, an inlet146 is also formed in the closure cap to permit fluid such as air underpressure to selectively enter recess 134 and overcome the bias of spring104 thereby advancing the piston and closure member toward theelastomeric sleeve. The tip 98 is advanced against the cylindricalportion of the sleeve and "pinches" the sleeve to a closed position(FIG. 6B). Removal of the air pressure from inlet 146 permits the spring104 to bias the piston and closure member back to a normally openposition, thus restoring the tip and sleeve to the FIG. 6A position.

A transparent shroud 148 extends outwardly from the closure cap andreceives the outer end of the stem 142. In a valve open position, thestem is clearly visible through the shroud. On the other hand, in thevalve closed position, the closure member has moved downwardly to pinchthe elastomeric valve sleeve so that the stem cannot be seen through theshroud. This provides a positive visual indication of the valve open andclosed positions.

According to the modified actuator embodiment of FIG. 5, the inlet 146is removed from the closure cap and opening 140 is enlarged to define anannular inlet passage 150. The shroud 148 includes an opening 152 at itsouter end for communication with an external fluid supply (not shown) topermit fluid flow to the upper face of the piston. This arrangementprovides for a dual use of the shroud 148 as both a valve open/closedindicator and the inlet for the remote actuator system. Still further,the modified actuator arrangement eliminates the use of one sliding sealmember, notably seal member 144. In all other respects, the modifiedvalve structure of FIG. 5 operates as disclosed with respect to theprevious embodiment.

When used in ultra-clean environments such as the biotechnologicalapplications discussed above, it is critical that all crevices in thefluid flow passage be eliminated to minimize the chance for entrapmentof particles. To accomplish this objective in the present application,and with particular reference to FIG. 4, the unstressed configuration ofthe elastomeric sleeve is illustrated in phantom while the final,assembled configuration is shown in solid lines. As is apparent, theaxial dimension of the unstressed sleeve is somewhat greater than thatof the central valve body. When the end members are brought into anassembled, sealing engagement with the valve body, the sleeve is axiallycompressed which results in a number of benefits. Particularly, thecross-sectional dimension of the sleeve opening 28 is reduced to closelyapproximate that of openings 84 in the end members. Stated another way,axial compression of the sleeve provides a radial expansion of thesleeve to eliminate any crevices between the body and end members. Anunobstructed, straight flow-through passage is thus defined by theassembled valve.

Axial compression of the sleeve also provides a primary seal between theend members and valve body. Thus, seal members 44, 48 are secondaryseals that guard against fluid loss should the elastic element rupture.They are not the primary seals. The radial outward expansion of theflanges also promotes a secure mechanical engagement between the sleeveand valve body along the shoulders 16 of the first and secondcounterbores 12, 14. This prevents pullout of the flanges resulting fromforces imposed by the closure member advancing and retracting betweenopen and closed positions.

Yet another advantage is realized by the compression of the valvesleeve. Prior arrangements molded a predetermined bulge into the centralportion of the sleeve to accommodate the tensile forces on the sleeve bythe pinch arrangement. By axially compressing the sleeve in the presentapplication and placing the sleeve in a compressive state, tensileforces do not arise in the sleeve until a point much later in theclosing stroke of the closure member 96. That is, the initial portion ofthe closing stroke transforms the sleeve from a compressive state to aneutral or non-compressive state. Further pinching of the valve sleeveduring the closing stroke results in tensile forces in the valve sleevebut these tensile forces are not encountered until much later in theclosing stroke then previous structures. Thus, the overall valve designhas a higher cycle life rating due to the lower tensile forces.Concurrently the pullout forces imposed on the flanges are reduced.

As is also apparent, the valve sleeve is only pinched from the upperside by the actuating mechanism as opposed to pinching fromdiametrically opposite sides of the sleeve. This is important from theaspect that the lower side of the valve sleeve as shown in FIGS. 1 and 2never undergoes any cycling or deformation. In the biotechnologicalfield it is imperative that the flow passage not be obstructed or formany traps for the fluid. By not actuating the lower portion of the valvesleeve drainability is enhanced.

FIGS. 7 and 8 illustrate a further modification to the general valveconstruction described above. For ease of discussion and illustration,like numerals will identify like components while new numerals will beused to identify new elements. The major modification resides in thevalve sleeve C and its receipt in the axial bore 10 of the valve body.More specifically, the bore 10 is of generally constant dimension andcomunicates with counterbores 160, 162 at opposite ends. Thecounterbores receive seal members 44, 48 that provide the sameback-up-seal arrangement between the central valve body and the endmembers as described above with respect to the O-rings 44, 48 in theFIG. 1 embodiment. Rather than providing separate grooves in an arearadially spaced from the bore 10, the modified structure permits thecounterbores 160, 162 to receive the seal members and advantageouslyfunction in the same manner.

The valve sleeve includes enlarged radially extending flanges 24, 26defined on opposite ends of cylindrical central portion 22. According tothis embodiment, though, the flanges maintain a generally constant axialdimension as they extend radially outward from central opening 28 of thesleeve. To provide the same secure mechanical engagement between thesleeve and valve body, rigid metal rings 164, 166 are defined in thesleeve flanges. More particularly, the rings are bonded through asuitable process to the elastomeric material of the valve sleeve. Therings serve a plurality of purposes. Primarily, the rings assure a closedimensional fit between the compressed valve sleeve and the end membersE. Stated in another manner, in the assembled valve the cross-sectionaldimension of the sleeve opening 28 closely approximates that of openings84 in the end members and the ring members assure that a close toleranceis achieved therebetween.

Secondly, the metal rings serve the purpose of providing sufficientrigidity to the flanges so that the axial compression imposed on thesleeve by the end members forms a primary sealing surface between thesleeve and end members.

Due to the difficulty in repairing and replacing valve sleeves in a bodyconfiguration such as shown in the FIG. 1 embodiment, the sleeve ismodified to include a second component comprising a casing member 170.The casing member is generally cylindrical and has an outer peripheraldimension 172 closely received in the axial bore 10 of the valve body.Smoothly contoured recesses 174, 176 are defined at opposite ends of thecasing member and merge into a generally constant diameter opening 178that closely receives the central portion 22 of the valve sleeve.Preferably, the casing member is formed of a material more rigid thanthat of the flexible valve sleeve. By way of example only, somepreferred materials of construction include plastic or metal. Thisprovides a sufficient backup surface for the sleeve as it is compressedaxially during assembly of the valve. The casing member also includes asidewall opening 180 that receives the rounded end 98 of the closuremember.

The two-part cartridge arrangement defined by the valve sleeve andcasing member 170 facilitates ease of replacement and maintenance of thepinch valve. The generally constant dimensioned outer periphery 172 ofthe casing member permits the cartridge arrangement to be axially slidwithin the bore 10. The entire cartridge arrangement can be replaced asa unit and eliminates any on-site manipulation of the enlarged radialflanges of the valve sleeve as encountered with an arrangement accordingto the FIG. 1 embodiment.

According to a still further modification, the outer diameter of thevalve sleeve may be provided with a support layer such as fabricreinforcement 186. This maintains some body or form to the flexiblevalve sleeve and provides a smooth transition surface between theflexible nature of the elastomeric sleeve and the more rigidconstruction of the casing member 170.

The entire closure cap 30 in the FIG. 7 embodiment is formed from atransparent plastic material to aid in monitoring the stem 142 of theactuating mechanism. This, of course, provides a positive indication ofthe valve open or closed position as described above.

In the manually actuated valve arrangement of FIG. 8, rotation of handle190 advances and retracts actuating stem 192 relative to the closure cap130. The means for advancing and retracting the actuating stem resultsfrom the well-known use of an external threaded region 194 on the stemand internally threaded opening 196 in the closure cap. A lower end 198of the actuating stem selectively engages an upper surface 200 of thepiston 122 to advance the rounded end of the closure member to a closed,pinched arrangement of the valve sleeve. In the pneumatic actuatedversion illustrated in FIG. 7, the actuating mechanism D is axiallyreciprocated in response to the selective application of fluid pressureto the upper surface of the piston. Spring 104 returns the piston andactuating mechanism to a normally open position. In order to increasevalve life, and particularly the cycle life of the flexible sleeve, inthe manually actuated valve it is necessary to minimize the transmissionof torque between the selectively rotatable actuating stem and thesleeve. Means for minimizing the torque transmission is provided by thestem gimbal 202 defined on the lower end of the stem. The gimbal is agenerally conical surface that provides point contact with the closuremember 96. Thus, axial advancement of the closure member is effectedthough the point contact without the transfer of rotary motion from theactuating stem to the closure member.

Turning now to FIG. 9, the pinch valve shown there is structurallysimilar to the modified embodiment of FIG. 7. Therefore, and for ease ofillustration, like elements are identified by like numerals and newelements are identified by new numerals. The closure member 96 alsoincludes a reduced diameter tip having a rounded end. Unlike the bladeconfiguration of FIGS. 1 and 2 or the cylindrical configuration of FIGS.6A and 6B, the rounded tip defines a generally horizontal,semi-cylindrical surface 210. Further reference to FIGS. 12 and 13assist in visualization of the configuration of surface 210. Thismodified tip distributes the closing forces over a larger surface of theflexible sleeve sidewall. As will be apparent to those skilled in theart, this structural arrangement provides effective valve closure andincreases the useful life of the flexible sleeve.

Another modification of the FIG. 9 embodiment is directed to a means forventing the valve body. Specifically, the venting means is defined by avent or weep opening 212 and the elimination of seal member 100 from thereduced diameter tip of the closure member. This combination vents thevalve body, particularly the normally sealed area defined by opening 86and counterbore 88 around the flexible sleeve. The venting means permitsthe area outside the flexible elastomer sleeve to openly communicate orbreathe with the ambient environment.

Incorporation of the venting means eliminates pneumatic closure forcesthat arise during valve cleaning. Typically, the pinch valve isautoclaved, i.e., subject to a sterilizing process that uses superheatedsteam under pressure. The entire valve body is subject to a temperatureincrease during the autoclaving process. In the embodiments illustratedin FIGS. 1-8, the area outside the flexible sleeve is sealed fromambient air. Thus, pressure in the closed area rises as the temperaturerises and the pressure imposes a pneumatic closure force on the flexiblesleeve. The described venting means eliminates this undesirable action.

Another advantage resulting from the venting means is that if theflexible sleeve fails, leakage through the vent opening is readilydetected. As illustrated in phantom in FIG. 9, a sight pipe or tube 214may be connected to the vent opening. The sight pipe aids in thedetection and to minimize spillage if a leak occurs. When processingexpensive biological batches, minimizing a spill can have a majoreconomic effect and/or permit salvaging the remainder of a batch beforecontamination develops.

Of course it is understood that some biological fluids cannot be leakedinto the environment under any circumstances. With such constraints, itis still desirable to eliminate pneumatic closure forces. One proposedsolution is to provide selective venting of the area outside theflexible sleeve. Accordingly, a valve schematically represented at 216may be secured to the sight pipe for selective communication between thevalve body interior and ambient air. By way of example, selectiveoperation of the venting means, particularly valve 216, provides an openpath during temperature excursions such as steam-in-place autoclavingand a closed path during biological batch processing.

Referring again to FIG. 9, and with additional reference to FIGS. 10-13,the horizontal semi-cylindrical tip 210 will be described in greaterdetail. To accommodate this tip configuration, the casing member 170 ismodified. The sidewall opening adopts a generally elongated orelliptical conformation 220 to freely receive the tip 210 therethrough.A first or upper component 222 of the two-part casing member maintainsthe smoothly contoured outer periphery 172 that is adapted for closereceipt in the bore 10. Likewise, the interior conformation remainssubstantially the same for closely receiving the flexible sleeve.

On the other hand, the interior conformation of a second or lowercomponent 224 of the casing member is altered to accommodate the"pinched" or closed valve sleeve. Preferably a planar area 226 extendslongitudinally and transversely along the interior surface of the lowercomponent 224. The planar area provides sufficient area into which thepinched sleeve may expand. Extending the planar area longitudinallyalong substantially the entire casing member, that is from end to end,prohibits formation of a dip or weir in the flexible sleeve that wouldimpair fluid drainability through the valve. The extent of the planararea in a lateral dimension decreases as it extends longitudinally froma generally constant dimension central region 228. Again, thisfacilitates receipt of the pinched sleeve in the lower component 224without constricting the flow channel. Stated in another manner, thepinching action of the tip 210 is not constrained by abrupt contours inthe lower component of the casing member. The flexible sleeve deforms asa result of the pinch action of the tip 210 and not from abrupt changesin the interior conformation of the lower component.

Lastly, the reinforcing or rigid rings 164, 166 may be modified asillustrated in FIG. 14. A series of apertures 230 are disposed in apredetermined pattern and extend completely through the rings. Theapertures permit elastomer flow during molding manufacture of thereinforced flexible sleeves. The apertures, in turn, aid in bondingbetween the rings and flexible sleeve to provide integral, reinforcedend flanges 24, 26.

The invention has been described with reference to the preferredembodiments. Obviously modifications and alterations will occur toothers upon a reading and understanding of this specification. It isintended to include all such modifications and alterations insofar asthey come within the scope of the appended claims or the equivalentsthereof.

Having thus described the invention, it is now claimed:
 1. A valvecomprising:a body having a bore extending therethrough; a flexiblemember received in said bore and having a passage defined therethroughadapted to be selectively opened and closed; a casing member receivedaround said flexible member and having an outer diametrical dimensionadapted for close receipt in said bore, said casing member including anaperture extending through a sidewall thereof; and, an actuating memberadapted for close receipt through said aperture for selectively engagingsaid flexible member and opening and closing said passage.
 2. The valveas defined in claim 1 wherein said flexible member includes radiallyextending flanges disposed at opposite ends, said flanges including arigid ring bonded thereto.
 3. The valve as defined in claim 1 whereinsaid flexible member includes a reinforcing layer along a peripheralportion thereof.
 4. The valve as defined in claim 1 wherein saidflexible member has an unstressed, first axial dimension greater than acompressed, second axial dimension defined between first and second endmembers in the assembled valve.
 5. The valve as defined in claim 1wherein said actuating member includes a closure member and actuatingstem, and means for minimizing transmission of torque from saidactuating stem to said closure member.
 6. The valve as defined in claim5 wherein said minimizing means includes a generally conical surfacedefined on one of said closure member and actuating stem.
 7. The valveas defined in claim 1 further comprising means for venting said body asan area around said flexible member.
 8. The valve as defined in claim 7wherein said venting means includes a valve for selectively venting thebody.
 9. The valve as defined in claim 1 wherein said casing memberincludes a planar area along an interior surface thereof accommodatinglateral expansion of said flexible member during valve closure.
 10. Avalve comprising:a body having a bore extending therethrough; first andsecond end members disposed at opposite ends of said body and havinginlet and outlet passages therein, respectively; a flexible memberreceived in said bore having a passage defined therethrough whichcommunicates with said inlet and outlet passages, said flexible memberhaving radially extending flanges at opposite ends each including arigid ring bonded thereto; a casing member received around said flexiblemember and having an outer, generally constant diametrical dimensionadapted for close receipt in said bore, said casing member beingsubstantially more rigid than said flexible member to provide radialsupport therefor along substantially the entire periphery of saidflexible member, said casing member further including an aperturethrough a sidewall thereof; and, an actuating member adapted for closereceipt through said aperture for engaging said flexible member andselectively opening and closing said passage.
 11. The valve as definedin claim 10 wherein said flexible member includes a reinforcing layeralong a peripheral portion thereof.
 12. The valve as defined in claim 10wherein said actuating member includes a closure member and actuatingstem, and means for minimizing transmission of torque from saidactuating stem to said closure member.
 13. The valve as defined in claim12 wherein said minimizing means includes a generally conical surfacedefined on one of said closure member and actuating stem.